The present disclosure relates to a touchscreen device and a method of driving the same.
A touchscreen device such as a touchscreen or a touchpad is a data input device attached to a display device so as to provide an intuitive user interface, and has recently been widely used in various electronic devices such as cellular phones, personal digital assistants (PDAs), and navigation devices. Particularly, as the demand for smartphones has been recently increased, touchscreens have been increasingly employed since they provide for various data input methods in a limited form factor.
Touchscreens used in portable devices may be mainly divided into resistive type touchscreens and capacitive type touchscreens, depending on the manner in which a touch is sensed thereby. Among these, capacitive type touchscreens have the advantages of a relatively long lifespan and ease of implementing various data input touches and gestures, and thus have been increasingly employed. In particular, capacitive type touchscreens allow for ease in the implementation of a multi-touch interface, as compared to resistive type touchscreens, and thus they are widely used in smartphones and the like.
The capacitive type touchscreen includes a plurality of electrodes having a predetermined pattern and the electrodes define a plurality of nodes in which changes in capacitance from a touch are generated. Nodes deployed in a two-dimensional plane generate a change in self-capacitance or a change in mutual-capacitance by a touch. Coordinates of the touch may be calculated by applying a weighted average calculation method or the like to a change in the capacitance generated at the nodes.
Patent Document 1 below discloses a touchscreen device that charges adjacent node capacitors with different voltages to differentiate the charges, thereby detecting a change in capacitance. However, Patent Document 1 does not teach determining a type of touch by a method of applying predetermined driving signals to outer electrodes among a plurality of electrodes extending in a single direction and detecting changes in capacitance from central electrodes.